I'm sure this will sound like a stupid question. But, this is my first 4x4 and I'd like to know how my machine works before I put it too use.

Now to the question. I've been told the 4x4's are actually only driving 3 wheels. How does this work? Is it similar to the limited slip of the rears or what? If it is how does it tell which side to send the power and can you somehow control which side is being powerd?

Thanks

 

There are 3 different options to throw into your differential. You may either have an open carrier (most common), limited slip or a locker. An open carrier will not have a set of clutches to limit any kind of slip whatsoever. An open carrier is very basic and will spin whichever tire has the least resistance. Search for Limited Slip on howstuffworks.com, they have great demo's of an open carrier. If you have an open carrier in the front & rear, in essence you have a 4x2 if there is resitance placed on your tires. It will still perform much better than a standard 4x2 with rear wheel drive because the tires will each take turns spinning. Take a look at my video and you'll get a good demonstration of this while I'm climbing a hill coming towards the camera.

There are a few types of limited slip, they can be driven by clutches or gears. Gear driven is far superior to the clutch type which is prone to wearing out on paved roads due to turning (the limited slip will become weaker over time). The Detroit Truetrac is a great gear driven LS and can be thrown in the front or rear, it will act as close to a locker as a limited slip can get and will perform well on road to boot.

You do NOT want a locker in the front of your F-150 if you drive onroad. You will get a ton of bucking, popping & chirping. This can do damage to your diff, driveshaft and other powertrain due to the amount of stress a locker places on these components. A locker is very self explanatory. It locks both wheels together so they turn at the same speed. Not a good design for turning. Some lockers are actuated by an air or electric source (air needs on board air compressor, electric is unreliable in water).

The F-150 can come with or without a limited slip in the rear, they do not offer the LS in the front. It is clutchpack driven. A limited slip differential will "give" well before it breaks anything drivetrain related (of course it is still possible to break things, but worlds less likely than a locker). When your friends say 4x3 they're talking about a limited slip in the rear and an open diff in front. If you can do a brake stand on pavement and leave 2 black marks you have limited slip in the rear. There are ways to manipulate a Limited slip when it does decide to "slip." A limited slip will do it's best to limit the slip and spin both wheels until it's torque rating has been surpassed. When this rating has been surpassed a method to help balance the torque rating back out is to apply the parking brake (not your pedal brake). Manipulating the parking brake will help torque the wheels evenly and might be enough to get you out of a sticky situation. If you have a front limited slip (unlikely unless aftermarket) the regular brake pedal will suffice.

If you have anymore questions try to read up on howstuffworks, it has some great information.

 

I know mine has the LS on the rear. Checked the axle code.

The front is completely stock. So, it's a clutch driven LS on the front of a bone stock 04 F-150?

 

You have an Open carrier regardless of F-150 model in the front.

 

Thanks a bunch. Think I have it straight now.